Apparatus for controlling fluid flow through drill strings



May 1,8 1943 l I as'. PENFIELD I 2,319,514

APPARATUS Fon coNToLLING FLUID FLow THROUGH DRILL STRINGS Filedsept. a, 1941 2 sheds-sheet I here memes; lo

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when is les i i the. r; m b iiise'ted e ower portion of the drin nnirgl string to control theiluid flow therethrough dur- `drill string and the restriction `under relatively, ing 'the operation of loweringsaid string into a `40 high pressure to erode away and remove said ,L bm-'ehem e Y `restricting means.

Further objects will be apparent from /the iol-v` To carry out the above method, various suitlowing description taken in reference to the folable restricting means may beused. Referring to lowing drawings wherein: l y 1 Figure III, a'` preferred embodiment of a now Figure I is a vertical sectional view ora bore` 45/ throttline devi-ce comprises a pipe nipple I havv,hole containing a drill string and mud fluid and `im; threaded ends 2' and 3, adaptable to be in-` illustrates `the drilllstring lowering step of the serted between kand to connect adjacent stands or 4present method. l w Y l lengthsof the drill string, as shown in'Figure I. Figure II is a vertical sectional view of a borel Filling the bore through saidnipple I is a plug 4, hole containing a drill-string and la mud fluid 50 which is axially-perforated as at 5. Suitable maf` and illustrates the step of removing therestrictterials from which plug 4 may be made include ng plug inthe present method. ,l concrete compositionsnatural and synthetic rubt Figure III is a vertical sectional view of a preber or mixtures thereof, Bakelite, soft metals or ferred embodiment of the present drill string now alloys,v soft mineral compositions, hard asphalt ltlhmttnug devma` l y y 55 or mixtures thereof, etc.; for example, a preferred composition is a mixture of cement and soap stone.

Referring to Figure IV, another embodiment of the throttling device comprises a pipe nipple IIl having an internal bead II at one end of the axial bore thereof and an external rib I2 on the other end of said nipple. I'he rib I 2 is adapted to fit in the joint between two sections of the `drill string such as,rfor examplerbetween the lowermost drill collar 32 and the double pin substitute 34 which is attached to the drill tubing 3| by coupling number 35, as vshown in Figure II. Likewise, in the bore of this nipple I is a plug I4 of suitable erodable material such as listed above, for example concrete, having an axial perforation I5 therethrough. The bead II serves to hold the plug in place but is insuiicient to appreciably impede normal iiuid circulation through the drill string after the plugging material is removed.

Referring to Figure V, still another embodiment of the throttling device comprises a centrallyperforated discr 20 of soft metal or alloy such as brass, lead, copper, tin, etc., or a hard plastic composition. Disc 20 is formed with a thickened outer circumferential portion or rib 2|, adapted to t in a joint between ltwo sections of the drill string. l

Referring to Figure I and II, in operation, a throttling device auch, for example, as that shown in Figure III, is :inserted'into the lower portion of a drill. string, such as between the tubing 3l and `the drill collar 32, while said portion of the drill string is at the surface; that is, while the drill string is being made up. The preferred position of the removable throttling device in the drill string is directly above the lowermost drill collar, that is, approximately 50 feet from the drill bit. The maximum possible distance between the throttling device and the bottom of the string is only limited by good practice, for example, within l 250 feet of the bit. With the throttling device in the desired position, the drill string is then lowterial is completely removed, the normal full bore .of the drill string is again available for circulation of drilling uid. Thus, the present invention permits the desired operation of restricting flow through the drill string during lowering thereof yinto a borehole and of quickly reopening the drill string to full bore without requiring any intricate manipulations. Upon withdrawing the drill string from the borehole again, the nipple I may be removed from drill string and refilled with a plug of suitable material for reuse.

To illustrate the conditions under which the ypresent method and apparatus are particularly applicable, the following average values which produce the undesirable overflow may be given by way of example: length of drill collars, 175 feet; outside diameter of drill collars, 7 inches; inside diameter of drill collars, 3.5 inches; inside diameter of drilling string, 4.892 or 3.754 inches; tool joints used, internal flush joint and mud viscosity, 23 centipoises.

, tially smaller than the outside diameter of said external member.

2.- A throttling device for tubular drill pipe strings comprising an external metallic annular member, external screw threads on the opposite axial ends of said member for xedly connecting said member between two drill pipe lengths, and an internal annular member bonded to said external member concentrically within said exterupwards and overflowing onto the derrick floor? Thereafter, mud-*circulation down through the drill string, which may be applied in a normal way or under somewhat increased pressure to accelerate the effect, quickly abrades or erodes away the soft plugging material ofthe flow control device. (Figure II shows an intermediate stage in the removal of the plug I4 of the ernbodiment of Figure IV.) After the plugging :ma-

external member.

nal member, said internal memberbeing made of abradable material, the axial perforation through said internal member having a diameter substantially smaller than the outside 'diameter of said 3. Av throwing device for tubular drin string comprising an external annular member, an exf ternal projecting annular rib on said external member for ilxedly clamping said member' be- Vtween;twogsgection.s of the drill string, andan internal annular member bonded to said externalmember concentrically within said external mem.- ber, said internal member being made of abrad- 1 able material, the axial perforation through said internal member having a diameter substantially CHARLES S. PENFIELD. 

